The actor has been living in rented homes since his split from wife Demi Moore last year (Nov11) and he booked one to stay in while he was filming TV sitcom Two and a Half Men - only to find it was on his young pal's wish list as he house hunted in Hollywood.
The two stars were promoting the new Punk'd show on U.S. late night programme Jimmy Kimmel Live! on Tuesday (27Mar12) when Kutcher explained how Bieber found the place he was renting.
He said, "I found this amazing house in L.A. that was on (website) AirBnB and I booked this house to stay in for, like, three months. I was away, I booked the house, it was all done and all of a sudden my assistant tells me there's somebody coming to look at the house to maybe buy it.
"I get a text from this guy (Bieber) and he's in my house, like, checking it out... He's like, 'Yo, I'm in your house right now...' He's like, 'Don't pay anymore than $9.5 (million) for it...' He's giving me real estate advice."
In order to secure the pad for himself and keep Bieber away, Kutcher reveals he had to buy the property: "I thought he was gonna buy the house from under me and I'm like, 'I don't wanna lose this house'."
Bieber has reportedly moved on to a spread in Calabasas, California, and is currently negotiating his first house purchase.
Meanwhile, Kutcher has also accused Bieber of stealing his dream car - a top-of-the-line, eco-friendly Fisker Karma which was a recent 18th birthday gift from the teenager's manager Scooter Braun.
The actor says, "It's my car... He's, like, trying to get my house and then he takes my car."